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 GNU Scientific Library Reference Manual - Third Edition (v1.12) by M. Galassi, J. Davies, J. Theiler, B. Gough, G. Jungman, P. Alken, M. Booth, F. RossiPaperback (6"x9"), 592 pages, 60 figuresISBN 0954612078RRP £24.95 (\$39.95)

## 19.21 The Logistic Distribution

Function: double gsl_ran_logistic (const gsl_rng * r, double a)
This function returns a random variate from the logistic distribution. The distribution function is,
p(x) dx = { \exp(-x/a) \over a (1 + \exp(-x/a))^2 } dx


for -\infty < x < +\infty.

Function: double gsl_ran_logistic_pdf (double x, double a)
This function computes the probability density p(x) at x for a logistic distribution with scale parameter a, using the formula given above.

Function: double gsl_cdf_logistic_P (double x, double a)
Function: double gsl_cdf_logistic_Q (double x, double a)
Function: double gsl_cdf_logistic_Pinv (double P, double a)
Function: double gsl_cdf_logistic_Qinv (double Q, double a)
These functions compute the cumulative distribution functions P(x), Q(x) and their inverses for the logistic distribution with scale parameter a.
 ISBN 0954612078 GNU Scientific Library Reference Manual - Third Edition (v1.12) See the print edition